PORT NUMBERS

(last updated 2008-05-12)

The port numbers are divided into three ranges: the Well Known Ports, the Registered Ports, and the Dynamic and/or Private Ports. The Well Known Ports are those from 0 through 1023. DCCP Well Known ports SHOULD NOT be used without IANA registration. The registration procedure is defined in [RFC4340], Section 19.9. The Registered Ports are those from 1024 through 49151 DCCP Registered ports SHOULD NOT be used without IANA registration. The registration procedure is defined in [RFC4340], Section 19.9. The Dynamic and/or Private Ports are those from 49152 through 65535 A value of 0 in the port numbers registry below indicates that no port has been allocated.

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* PLEASE NOTE THE FOLLOWING: *
* *
* IESG STATEMENT TO THE IANA *
* THE IESG BELIEVES THAT IANA MAY ALLOCATE AN ADDITIONAL PORT IN *
* THE ‚USER PORT‘ RANGE TO PROTOCOLS WHOSE CURRENT PORT ALLOCATION *
* REQUIRES ACCESS TO A PRIVILEGED PORT. THIS ALLOCATION SHOULD NOT *
* BE AUTOMATIC, BUT MAY OCCUR UPON APPLICATION BY AN INTERESTED *
* PARTY WHOSE APPLICATION WOULD OTHERWISE FIT IANA’S POLICIES. *
* *
* 1. UNASSIGNED PORT NUMBERS SHOULD NOT BE USED. THE IANA WILL ASSIGN *
* THE NUMBER FOR THE PORT AFTER YOUR APPLICATION HAS BEEN APPROVED. *
* *
* 2. ASSIGNMENT OF A PORT NUMBER DOES NOT IN ANY WAY IMPLY AN *
* ENDORSEMENT OF AN APPLICATION OR PRODUCT, AND THE FACT THAT NETWORK *
* TRAFFIC IS FLOWING TO OR FROM A REGISTERED PORT DOES NOT MEAN THAT *
* IT IS „GOOD“ TRAFFIC. FIREWALL AND SYSTEM ADMINISTRATORS SHOULD *
* CHOOSE HOW TO CONFIGURE THEIR SYSTEMS BASED ON THEIR KNOWLEDGE OF *
* THE TRAFFIC IN QUESTION, NOT WHETHER THERE IS A PORT NUMBER *
* REGISTERED OR NOT. *
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WELL KNOWN PORT NUMBERS

The Well Known Ports are assigned by the IANA and on most systems can only be used by system (or root) processes or by programs executed by privileged users. Ports are used in the TCP [RFC793] to name the ends of logical connections which carry long term conversations. For the purpose of providing services to unknown callers, a service contact port is defined. This list specifies the port used by the server process as its contact port. The contact port is sometimes called the „well-known port“. To the extent possible, these same port assignments are used with the UDP [RFC768]. The range for assigned ports managed by the IANA is 0-1023.